I think the issue is that the interviewee doesn't always know what is on the "test". It is also a waste of everyone's time. If a company's only data store is SQ

I think the issue is that the interviewee doesn't always know what is on the "test". It is also a waste of everyone's time. If a company's only data store is SQL of some kind, which do you want: Someone who can barely do joins but has memorized red/black tree function implementations in several languages or some one who knows SQL at a production level and if they had to do something with red/black trees would just have to spend a day or two re-reading how they work? I think the thing this underscores is that we really need an association like the "bar". So you can go study all the things on the test and prove you have the knowledge and ability and then skip that as part of hiring and just focus on experience. The only thing we have today is tech company specific certification which is okay for certain things but not for more general software needs.